Significance This study demonstrates that brain function can be compromised by marginal intake of iron and zinc from the diet during the period of the adolescent growth spurt. Objectives The purpose of the study was to marginally deprive rhesus monkeys of iron during their adolescent growth spurt, and then to determine whether provision of iron and zinc as meat protein would reverse the effects of the deprivation. Two behavioral tasks, an attention task and a learning tasks, were administered throughout the period of deprivation and reversal, and standard measures of iron and zinc deficiency and of growth were also studied. Results Plasma zinc and iron decreased during the deprivation period. The marginal iron and zinc deficiency did not interfere with adolescent growth and puberty was not delayed. All monkeys (female rhesus, 30-36 months old) experienced changes in hematology during the growth spurt, and some of these were exaggerated in the iron-zinc deprived group (n=8/group). In the behavioral task improvement in attention performance was impaired and slower responses were noted in the learning task. The meat protein supplement reversed the attention impairment but not the effect on speed of responding. Future Directions We are also studying iron deficiency effects on behavior using a mouse model. A study using both mouse and monkey models and addressing concerns in human malnourished populations is under discussion. Three abstracts describing these results have been submitted for presentation during 1998. KEYWORDS iron deficiency, zinc